Electrical conductor



mi! 28,1936. H. w. PAPST 2,039,9 5

ELECTRICAL- cor'muc'ron.

Filed Aug. 8, 1934 WITNESSES I- Patented Apr. 1936 PATENT OFFICE CONDUCTOR Hugh W.

Papst, Pittsburgh, Pa.,

assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa,

Pennsylvania a corporation of Application August 8, 1934, Serial No. 738,981 s (01. 173-13) My invention relates to electrical conductors and more particularly to bus bars for use-in multi-phase power systems.

An object of my invention, generally stated, is to provide a bus bar structure which will be highly eflicient in operation and which may be economically manufactured and installed.

A more specific object of my invention is to provide a simple and economical means of supporting a multiphase bus bar structure.

Another object of my invention is to provide a bus bar arrangement which shall have a low inductance.

It is known that tubular conductors will transmit alternating currents more eillciently than solid duced rent. In view of the difiiculty of mounting tubular conductors, various schemes have been proposed in which either fiat bars or channel bars are so mounted as to provide a hollow square arrangement having the desirable features of tubular conductors relative to current-carrying capacity.

However, where currents beyond the limits of an ordinary multiple-bar bus must be carried, it is advisable to utilize a form of interlaced conhas numerous advantages over previously known bus bar an'angements, as will be set forth hereinatter.

In accordance with the preferred embodiment of my invention, structural angle barconductors are concentrically mounted in insulating supporting members and the succeeding phases of a multi-phase system ,are carried within the first phase.

For a fuller understanding of the nature and obof my invention, reference may be had to junction with the accompanying drawing, in which:

Figure 1 is an end view, partially in elevation and partially in section, of a bus bar arrangement constructed in accordance with my invention; i

Fig. 2 is a view, similar to of a modified form of the showing a method of Fig. 1, of a portion bus bar structure, making branch connections to the main bus bars, and

in Fig. 1, designated Fig. 3 is a view partly in elevation and partly in section, of a modification oi the invention, showing one pair of angle bars mounted to form a single conductor.

Referring to the drawing, and particularly to Fig. 1, the bus bar structure shown comprises a plurality o1 angle bars I0, which may be composed of any suitable conducting material such as copper or aluminum. As shown, the angle bars I are disposed in spaced relation with the corresponding legs of the bars substantially at right angles to each other, the bars being mounted obliquely so that the vertices of the angles are in a substantially horizontal plane, thereby providing vertically opposed ventilation openings be- 5 tween the bars, which permits a free circulation of air between the conductors, resulting in higher current ratings per unit of conductor.

If it is desired to provide onlya single conductor, one pair of angle bars may be mounted in a manner similar to that of the inside pair of bars by the letter C, or the conductors may be mounted as shown in Fig. 3, thereby forming a hollow divided conductor of rectangular cross. section and having vertically opposed ventilation openings which provides an improved ventilating scheme, the air being allowed to pass through the conductor vertically from the bottom to the top of the conductor.

For multi-phase power systems, as for example, a three-phase system, the conductors may be arranged in the manner shown in Figs. 1 and 2, in which a pair of angle bars is provided for each phase and the pairs of angle bars are concentrically mounted with the vertices of all the an- 3 gles disposed in a horizontal plane. Thus, the inner pair of conductors marked C may be connected to phase C of the power system, the next outer'pair of conductors marked B may be connected to phase B and the outermost conductors 40 marked A to phase A of the power system. By thus concentrically mounting the conductors for all three phases, with each successive phase disposed within the first, the inductance of the bus bar arrangement is greatly reduced and, accordingly, the reactance voltage drop of the system is reduced. 7

Furthermore, the amount of space required for a multi-phase bus bar structure may be reduced considerably byarranging the conductors in the manner herein shown and described; also the conductors may be supported in a simple and inexpensive manner.

In the structure shown in Fig. 1, the angle bars 1 III are retained in spaced relationship by lnsulating members H, which are similar in design, disposed at the top and also at the bottom of the conductors. Each insulating member i2 is provided with six notches ii for receiving the tips of the legs of the angle bars in. The'insulators I! are mounted on transversely disposed channel bars H which are secured to longitudinally disposed angle bars i5 at the four corners of the bus bar structure, the angle bars i5 being parallel to the bus bar conductors Iii and extending practically the full length 01' the bus bar structure.

The insulators I! may be secured to the channel bars H by means of bolts 16 and the channel bars I4 are secured to the angle bars i5 by through bolts l'i. Spacing sleeves iii are provided on the bolts IT to prevent the insulating members I! from being drawn too tightly against the an gle bar conductors. This construction permits the conductors to move freely in a lengthwise (iirection as the result of any expansion or contraction that might take place, thereby preventing warping or buckling of the conductors.

It will be understood that the combined insulating and supporting members may be placed along the bus bar structure at desired intervals to retain the conductors ID in definite spaced relationship. It will also be understood that the structure shown is largely self supporting, the conductors l serving to strengthen the structure.

The bus bar structure shown in Fig. i is designed tor outdoor service and is enclosed for protection from the elements and also from contact by persons or animals. The enclosing structure comprises sheet metal side members 2|, which may be attached to the angle bars I and a cover structure 22, which may be secured at the upper edges of the side plates II by means of U- shaped members l9, provided at desired intervals. A metal screen 23 may be provided along the bottom of the bus bar structure, thereby affording protection from contact with the conductors but permitting a free circulation of air between them. The air is permitted to enter the enclosure through the screen and pass out through the spaces provided between the cover 22 and the top of the side plates 2|, after vertically traversing the bus bar phases to effectively ventilate them. In this manner an enclosure may be provided which is entirely supported by the bus bar structure.

Supporting members 24 may be attached to the sides of the bus bar structure, at desired intervals, to mount the structure on pillars or a wall (not shown), thereby providing all the supporting means required for mounting the bus bar structure in any location.

The bus bar structure shown in Fig. 2 is designed for indoor service, therefore a cover structure is not required. may be enclosed by a metal screen, similar to the screen 23, if desired, to prevent persons from coming in contact with the conductors. The structure shown in Fig. 2 comprises a plurality of angle bars l0 disposed in the same manner as in Fig. 1. The conductors in are retained in spaced relationship by insulating members l2a, which may be of a slightly different design than those shown in Fig. 1. The insulators Ila are mounted in transverse channel bars I disposed above and below the conductors Ill. The upper and lower insulating members l2a are drawn together to engage the angle bars in by means of through bolts I'I. However, as in Fig. l, spacing sleeves iB are placed between the insulators to prevent the in- However, the conductors sulators from clamping the conductors too tightly, thereby permitting longitudinal movement of the conductors.

As shown, branch or feeder connections may be readily made to the main bus bars by means of conductors 25, which may be welded to the angle bars, or secured thereto in any other suitable manner.

In the modification of the invention shown in Fig. 3, a pair of angle bars ID are so mounted on insulating supports or pillars 26 that they form a hollow divided conductor of rectangular cross section. The angle bars are mounted obliquely with the vertices of the angles disposed in a hortaontal plane, as in tion and the bars are retained in spaced relationship b recessed clamps 21, which. engage the tips of the legs of the angle bars. A centrally disposed stud bolt 28 serves to draw the top and bottom clamps 21 together, a spacing sleeve It being provided to prevent the angle bars from being clamped so tightly that they cannot expand longitudinally without buckling. The combined insulating and clamping means shown may be installed at desired support the angle bar conductor, thereby pro viding an inexpensive and efficient bus bar structure.

From the foregoing description, it is apparent that I have provided a bus bar structure which has numerous advantages over previously known structures. Some of the advantages of the invention are; the reduced space required for a multi-phase bus structure and the low inductance of the arrangement, which results in a low reactance voltage drop and improved power-factor conditions in alternating-current systems. The present structure also provides a better self-ventilating arrangement, which permits higher current ratings for the conductors.

Since numerous changes may be made in the above-described construction, and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all matter contained in the ioregoing description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention: a

1. A multi-phase bus bar structure comprising a plurality of pairs of angle bars concentrically mounted with the corresponding legs of each pair of bars disposed substantially at right angles to each other, the vertices of the angle bars being in a substantially horizontal plane, and combined insulating and supporting means for retaining the angle bars in spaced relationship to provide vertically opposed ventilation openings between the angle bars, each successive phase of the structure being disposed within the preceding phase.

2. A multi-phase bus bar structure comprising a pair of angle bars for each phase, said pairs of angle bars being concentrically mounted with the corresponding legs of each pair of bars disposed at substantially right angles to each other, the vertices of the angle bars being in a substantially horizontal plane, and combined insulating and supporting means for retaining the angle bars in spaced relationship to provide vertically opposed ventilation openings between the angle bars.

3. A multi-phase bus bar structure comprising a pair of angle bar conductors for each phase, said pairs of angle bars being concentrically the other forms of the inven intervals along the bus bar to i mounted with the corresponding legs 0! each pair o oaaees of bars disposed substantially at right angles to each other. the vertices of the angle bars being in a substantially horizontal plane and the conductors for each successive phase being disposed within the first phase. and means for retaining the bars in definite spaced relationship.

4. A multi-nhase bus bar structure comprising a pair of L-shaped conductors for each phase, said pairs of conductors being concentrically mounted with the conductors for each successive phase being disposed within the first phase, and combined insulating and supporting means for 33 retaining the conductors in definitely spaced relationship.

5. A three-phase bus bar structure comprising three pairs of angle bar conductors, one pair'tor each phase, said pairs of angle bars being concentricaily mounted with the conductors for each successive phase disposed within the first phase, the vertices of the angle bars being in a substantially horizontal plane, and insulating means for engaging the ends of the legs of the angle bars to 10 support said bars.

HUGH W. PAPBT. 

